APRIL 26, 1901.] 
volts, being capable, however, of regulation 
through a wide range. The tops of the 
alternating current waves of high potential 
obtained from this secondary transformer 
were used to charge a number of glass plate 
condensers in parallel. The rotating frame 
synchronously driven with the motor made 
the connection to the condensers period- 
ically and insynchronism with the alternat- 
ing current. The connection by the rotat- 
ing frame is alternately in parallel and in 
series, the condenser plates being charged to 
15,000 volts with ten in parallel, giving 
150,000 volts when connected in series. 
The machine therefore furnishes from low 
pressure direct current, high potential dis- 
charges of definite polarity at the discharged 
terminals. The new rotary electrical ap- 
paratus consisted of an iron sphere heavily 
electroplated with copper and mounted so 
that it may revolve on any axis or in any 
plane. Surrounding this sphere were three 
coils in planes at right angles to each other. 
By suitably energizing these coils with poly- 
phase current the sphere was made to re- 
volve on any axis or in any direction, thus 
illustrating a three dimension polyphase 
system. This apparatus shows in a very 
satisfactory manner the principles of the 
gyroscope and Bohnenberger sphere. 
Professor Thomson also exhibited an 
aluminum disc mounted on a shaft free to 
rotate, and having applied to it in special 
ways alternating current magnetic fields, 
the rotations of the disc involving interest- 
ing paradoxes which the visitors were asked 
to explain. 
Mr. E. VY. Baillard showed the Parker- 
Baillard bridge for measuring low electrical 
resistances for general work and standardi- 
zation and an ingenious faradmeter for the 
direct measurement of capacity. Some in- 
teresting spark experiments, showing oscil- 
lating discharges occurring rapidly during 
the same half wave, and proving that a short 
circuit in a high potential current containing 
SCIENCE. 
657 
inductances and capacity ruptures itself in- 
stantly, were shown by Mr. W.S. Andrews 
who also exhibited a luminous aluminum 
cell giving beautiful effects. 
Among the many other exhibits were 
various forms of storage batteries by Mr. 
Elmer A. Sperry, Mr. Herbert Lloyd, Mr. 
A. §. Hubbard and Messrs. Frank Perret, 
J. A. Barrett, and W. H. Meadowcroft. 
Mr. H. R. Palmer showed a fac-simile pic- 
ture telegraph in operation, Mr. Otto T. 
Louis an electric furnace and an ohmmeter. 
A specimen of the standard United States 
Army field telephone and telegraph kit used 
in the Cuban and Philippine campaigns, and 
wireless telegraphy as improved by the 
Government, were in charge of Col. Samuel 
Reber, U.S. A. 
W.C. ANDREWS. 
SCIENTIFIC BOOKS. 
Erinnerungen aus meinem Leben. Von A. K6x- 
LIKER. Leipzig. 1899. 8vo. Pp. x + 399. 
This work of the veteran celebrated histolo- 
gist is much more than an autobiography, since 
it includes a number of original contributions 
to science, with which the anatomist and em- 
bryologist must necessarily acquaint them- 
selves. 
The first part is strictly biographical, giving 
a general account of the author’s life, which 
passed without exciting elements along aca- 
demic paths. Kolliker was born at Zurich, in 
Switzerland, on July 6, 1817, the elder of two 
children. He dwells somewhat upon the recol- 
lections of his boyhood, recalling with pleasure 
a few boyish escapades. He early displayed ~ 
great fondness for nature ; he loved the moun- 
tains and made collections of plants and min- 
erals, and therefore was led naturally to the 
study of medicine. But practice had no al- 
lurements for him, especially since he soon fell 
under the spell of the microscope, as a reveal- 
ing instrument, in the employment of which he 
has spent his long life. In the summer of 1839 
he went to Bonn, hearing there medical lec- 
tures in Latin, and the autumn of the same 
year he passed to Berlin and came under the 
